It is today a known procedure to use different kinds of prefabricated elements when erecting a building complex. Already in the 1960's, and perhaps even before that, the concept of building prefabricated modules was used. The modules could e.g. include a bathroom, a kitchen or the like. This module would then be compatible to be installed in a building complex; cf. for instance GB-A-1,213,009.
EP-A-462,790 discloses a building system which comprises rooms formed from prefabricated room units, wherein the units include walls and a ceiling. The room units are arranged in rows where each row has adjacent pairs of room units and where each pair of units is structural mirror images of each other. Even though the elements are prefabricated there is still a lot of work to be done with the interior before the building may be ready to use as e.g. a hotel. The work at the construction site is time-consuming and expensive since many workers must be hired to finish the interiors. Hence, this known system involves high costs which probably is the main reason why it has not been put into practice.
US-A-2005/0108957 describes a prefabricated module which is intended to be used in a multi-storey building. The modules may contain a bathroom, a kitchen, a staircase or a combination of the previous mentioned and may be stacked on top of each other and then installed concurrently with the surrounding structure. One module may be configured to have a dual room layout which means that the module will include e.g. two bathrooms which are a mirror image of each other. Additionally, each module has a vertical shaft which includes features like water supply, waste sewage and ventilation shaft. This known system is complicated and suffers from the same problem as the costly system described above.
As to background art, WO-A-2006/13653 could be mentioned as well since it discloses a prefabricated service pod. However, this publication does not suggest low-cost prefabrication based on non-complex structures. Hence, the proposed service pods are not suitable for building projects of the type today's market demands.
Prefabricated elements for buildings do not only include service pods and the like, but also various types of wall and panel elements. An example of such an element is disclosed in EP-A-565,842. However, this known element only constitutes a part of a building and the publication does not suggest any overall solution to the problem of how to construct an entire building which meets today's requirements of low-cost construction projects to be performed under time pressure.
The choice of building method normally depends on which type of house to be built and for what purpose. Although known building methods may differ in many ways, most of them are time consuming. As construction time is a crucial factor for the cost efficiency of the building, there is always a need for improving the erecting methods, especially for large and complex buildings such as multi-resident buildings or the like.
WO-A-2008/102152 describes a method of constructing a building with prefabricated modules, wherein each module defines a room with e.g. a bathroom area. The modules may be identical or of two different types, and they are configured to be stacked upon each other to form a multi-storey building.
WO-A-00/34593 discloses a building method using two different kinds of modules, i.e. a U-shaped module and an L-shaped module. The modules are combined on site to form the bearing structure of a multi-storey building. Since the modules are not pre-fabricated there are many partial challenges with this building method. Particularly, the proposed building method is disadvantageous since all the different parts of the partial modules must be manufactured with high precision to fit each other. More parts and partial modules will increase the risk of making a mistake in the production or the assembly. Many parts of different sizes and shapes also become a problem when transporting them to the erection site. The space of the transportation may then not be optimized for the parts packed in it. The proposed method is thus not very flexible since the different shapes of the modules require specially adapted logistic resources.
Another example of a building method is described in CA-A-2,046,217. In this document a solution is proposed involving a building unit which comprises at least four dwelling units which are supposed to be connected to each other, horizontally or vertically. The dwelling units comprise modules which include different types of interior depending on its location and purpose.
In view of the building methods previously presented there is still a need for an improved method which allows a reduced erecting time.